This invention relates to a composition and method to treat abnormal blood vessel proliferation in the eye.
Many therapeutic treatments of pathological conditions involve selective targeting of specific tissues or cells for destruction. For example, a goal in cancer therapy is to destroy only malignant cells while leaving normal cells undisturbed. As another example, a goal in ophthalmology is to destroy new abnormal blood vessels in the eye that can result in visual impairment if allowed to proliferate, while leaving normal existing blood vessels intact.
In the mammalian eye, macular degeneration (also called age related macula degeneration, AMD) is a pathological condition that results in proliferation of new blood vessels in the subretinal area. The new blood vessels proliferate from the choriocapillaris through defects in Bruch""s membrane beneath or on top of retinal pigment epithelium (RPE), and form vascular membranes. While the presence of the new vessels themselves is not problematic, new vessels leak blood and other serous fluid which accumulate in surrounding spaces. It is this fluid accumulation that leads to visual impairment. For example, in the retina, both the large vessels and the capillaries normally have intact vessel walls. In the choroid, the large vessels normally have intact vessel walls, but the capillary walls or membranes contain fenestrations or openings. Any endogenous or exogenous fluid present in these capillaries, for example, blood, serous fluid, solubilized drug, etc. will leak outside the vessels and into the surrounding area. The accumulation of fluid can result in serous and hemorrhagic detachment of the RPE and neurosensory retina, and can lead to loss of vision due to fibrous deform scarring. More than 90% of cases having significant loss of central vision in AMD are attributed to choroidal neovascularization and the resulting exudation and scarring. Choroidal neovascularization occurs in about 8-10% of all patients with AMD, and is also seen in patient with pathologic myopia and presumed ocular histoplasmosis syndrome, as well as other idiopathic conditions.
Simply put, control of blood vessels is a way to treat certain pathological conditions such as macular degeneration. Macular degeneration results in new, inherently xe2x80x9cleakyxe2x80x9d, blood vessels in the eye. These new leaky vessels allow fluid to escape and pool in the surrounding tissues. The accumulation of fluid results in scar formation which can damage the eye and lead to altered vision. A goal is to destroy the new abnormal blood vessels and/or to prevent their growth.
Thus, a method to prevent or control the growth of subretinal blood vessels is needed. Such a method will in turn protect vision by protecting retinal integrity.
The invention is directed to a therapeutic method to treat or prevent abnormal blood vessel formation and proliferation. Such an invention is useful in a variety of pathological conditions, for example, abnormal blood vessels in the eye as occurs in macular degeneration.
The method uses hypocrellin compounds. A member of the hypocrellin class of compounds is administered to reach the vessel and is photoactivated in the vessel. The hypocrellin class includes hypocrellin A, hypocrellin B, and derivatives such as amino-substituted hypocrellin B.
This invention will be further described in the following figure, detailed description and example.